Frequently Asked Questions - Paper Presenters

I have already agreed to participate in one workshop (with no paper) and now I am being asked to participate in a session in which I am given the choice of: being a discussant or giving a paper. I am unsure if I can accept the second invitation and in which capacity.

Can I present a paper on one session and be listed as a workshop/roundtable participant on another?

Is a workshop/roundtable participant considered a paper presenter?

Can I participate as co-author for one paper and main author for a different one?